The impact of zotepine onthe excitatory synaptic response and long-term potentiation in the hippocampus of rabbits

Abstract

：Objective To observe theimpact of zotepine on the excitatory synaptic response and long term potentiation (LTP) ofdentate gyrus neurons.Methods Male rabbits ( n = 20) weighting about 2.5 ～ 3.5 kg were divided into four groups randomly ( n = 5 ): control,zotepine 1.0, zotepine 2.0 and zotepine 5.0.To each rabbit,there were 60 results during120 min.Population spike(PS) amplitude and excitory postsynaptic potential (EPSP) slopewere used to be the indexes of the excitatory synaptic response of dentate gyrusneurons.The sequence was base response ( at the beginning), intraperitoneal injection of0.5ml dimethylsulfoxide or 0.5ml zotepine-dimethylsulfoxide solution ( 1.0,2.0,5.0 mg/kgof zotepine dosage) ( after 30 min) and titanic stimulation (after 90 min).Results To 4groups,the PS amplitude and EPSP slope after single stimuli were not significantlydifferent from those before single stimuli.In control group, the PS amplitude and EPSPslope after titanic stimulation[(0.68 ± 0.052)mV and(0.633 ± 0.024 )mV/ms] weresignificantly different from those before injection[(0.266 ±0.008) mV and(0.246 ±0.010)mV/ms] (P＜0.05 ～0.01 ) ,and LTP wereinduced.LTP were not induced after titanic stimulation in group zotepine 1.0,2.0 and5.0.After titanic stimulation, the PS amplitude and EPSP slope in group zotepine5.0[(0.277 ±0.008)mV and(0.296 ±0.007) mV/ms] were significantly different from those ingroup control(P＜ 0.05).Conclusion Zotepine had little effect on the excitatory synaptic responseof dentate gyrus neurons after single stimuli in perforant path, while it blocked theinduction of LTP in perforant path-dentate gyrus pathway. Key words: Zotepine; Perforant path; Dentate gyrus; Long-termpotentiation